I've done some Google searches but I'm not sure I'm looking for the right thing or even using the right phrase... Is there such a product that I can plug my headphones into and stream music to from my MBP? I live in a small flat with thin walls and would like to not be tethered by a cable when I'm working late at night or doing stuff in the kitchen. I don't want to buy yet another pair of special infra-red or bluetooth headphones as I've got some OK Sennheisers and a pair of Shure e4cs already. Just something the size of an iPod, that you can plug some headphones into, that takes some batteries and can take bluetooth or wireless? Anything like that exist out there?